Alcohol misuse is linked to extensive economic costs as well as a large number of injuries and deaths. An estimated 16.6 million adults 18 and older had an alcohol use disorder (only one of which is Alcoholism) in 2013, amounting to ~$24.6 billion in healthcare costs. Additionally, nearly 88,000 deaths per year have been attributed to alcohol-related causes. Alcohol misuse is the number one leading risk factor for premature death for those aged 15-49, and the fifth leading risk factor for death overall. A high incidence o binge drinking (24.6% of people 18 or older in 2013) is indicative of the underlying problem. In light of this, tools that help to prevent excessive alcohol consumption serve an important role in reducing the enormous human and socio- economic costs associated with alcohol misuse. The ability to responsibly and personally track Blood Alcohol Concentration (BAC) levels could result in a significant reduction of alcohol related injuries and deaths. In addition, patient compliance n terms of regular monitoring and reporting of BAC is one of the major concerns and needs for the treatment of Alcoholism. Currently, the most accurate method for measuring BAC is to directly and invasively sample the blood and perform an assay, and is therefore not amenable to widespread use. Non-invasive measurement of Breath Alcohol Concentration (BrAC) is popular but conspicuous, and of questionable accuracy (variable by 50% from true BAC). Several non-invasive, wearable devices are available that measure Transdermal Alcohol Concentration (TAC). However, TAC is a poor reflection of BAC, being delayed by 30-90 minutes and prone to error by attempting to detect the small amount of alcohol that makes it to the skin. There is therefore a need for non-invasive measuring of BAC directly. Lynntech proposes to develop a wearable device that accurately and non-invasively measures BAC. The device will be programmable, unobtrusive, appealing to the wearer, and can take the form of a modern wristwatch that communicates with a mobile device to enable feedback and maintain user intoxication awareness. We hypothesize that, with lessons learned from the highly mature field of pulse oximetry, a true and direct measurement of BAC can be achieved using spectroscopy. In the Phase I, we have designed our aims with the goal of developing a prototype non-invasive BAC measuring device. These aims include: 1) developing the BAC measurement device hardware and software; 2) optimizing the BAC measurement using in vitro and ex vivo models; and 3) demonstrating accurate, real-time BAC measurement in vivo. A prototype device using high intensity LEDs and appropriate photodetectors will be designed and programmed. The assembled device will be used to demonstrate the feasibility of measuring alcohol content in the blood through a sample of porcine skin. Results will be used to optimize device design, configuration, and operation. Finally, the optimized device will be demonstrated in a mouse model to prove full feasibility. This effort is an integral part of a more comprehensive Technology Development Plan that is described in the Budget Justification.